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<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <!--table>tr>td*4-->
  <table border="1" width="1000" align="center">
    <tr>
      <td>A1</td>
      <td>A2</td>
      <td>A3</td>
      <td>A4</td>
    </tr>
    <tr>
      <td align="center" colspan="4">B1</td>
    </tr>
    <tr>
      <td colspan="2">C1</td>
      <td colspan="2">C2</td>
    </tr>
  </table>
</body>
</html>